Maintenance of greens
Proper management of greens will ensure high turf quality. The following is a listing of our recommendations for proper turf management.

Fertilizing
Without nutrients, no growth occurs – and growth is a prerequisite for a high quality lawn. A fertilization plan should be prepared on the basis of soil analyses. Generally greens should be fertilized monthly from mid-April through the end of September.

Precision fertilization is possible with simple equipment

Cutting
The height at which the grass is cut has a heavy impact on the growth of the grass. The normal height of the grass on lawns/football fields is usually 1.25 to 1.5 inches (3.0 – 3.5 cm). The type of games played on the lawns /football fields etc. often calls for a height of 3/4 to 1 inch (1.8 – 2.8 cm). Nevertheless, this reduces the vitality and wear tolerance of the grass, as well as its resistance to pests and diseases. The height and frequency of the cutting should be varied according to the growth of the lawn. Only one third of the leaf length should be removed at each cutting. Decorative lawns, sports fields etc. should be cut with a reel mower, which does not tear the grass. This will minimize the risk of disease.

Vertical cutting
Old grass cuttings, dead leaves, stems etc. can form a layer of non-decayed plant material called “thatch” at the bottom of the plant. A lawn with a thick thatch layer will slowly degenerate because the water, fertilizers and air cannot penetrate properly into the soil beneath. Under moist conditions, a thick thatch layer can also make the surface of the grass spongy and increase the risk of disease. Furthermore, the thatch layer reduces the wear tolerance of the surface, furthering the formation of bare spots which will allow weed seeds to germinate quickly. 

Since the thatch layer influences the growth of the grass negatively, lawns must be cut vertically. Knives cut the thatch layer at intervals of 3/4 to 1 inch. During this procedure, the plants are cut, thus creating new, independent plants and more tillers.

Vertical cutting must be done in the spring or fall, but never in dry periods. Fertilizers should be distributed right after the vertical cutting.

Illustration of the effect of vertical cutting

Small machine for vertical cutting. On large areas bigger machines are needed. 

Re-seeding
When using lawns/sport fields intensively, bare spots appear inevitably, and require a re-seeding. Re-seed when worn patches appear on the lawn/field. Re-seeding is carried out with special machines, which either cut down into the grass layer to place the grass seeds into grooves at a depth of 1/3 of an inch (1 cm), or prick small holes and sow the seeds over the entire area. In the same process, some machines can also top dress to cover the seeds. 

Seeding can be done with simple equipment if vertical cutting has been done prior to overseeding. In principle, re-seeding can be carried out throughout the entire growth period. However, the best seeding periods are in the spring and fall.

This type of machine places the seeds in small holes to improve establishment.

Top dressing
Top dressing is a prerequisite for a high lawn quality. Top dressing keeps the lawn even, protects the lawn growth area, and ensures a better germination on re-seeding. A top dressing helps stimulate the growth and vitality of the grass. Top dressing materials are sand, sandy loam, or a sand-compost mixture. When choosing the top dressing, the range of grain sizes is important. If sand is used, it is recommended to mix it with loam or compost. However, the compost should make up no more than 25-30% of the mixture by volume. 

Topdressing with sand

Dragging with a net to level topdressing

Subsequent to top dressing, leveling by means of a harrow is recommended, and is normally done in connection with vertical cutting and re-seeding.

This type of net for dragging is also for surface leveling 

Aeration
The use as well as maintenance of the lawn/field will often lead to compaction of the top 2-3 inches (5-8 cm) of the soil.This reduces the growing conditions of the grass. Aeration can, to some extent, remedy the problem. The need for aeration is most important in April, September and October.

Various types of aeration machines are available

Loosening the soil
When not only the top few inches of the soil, but the top foot has been compacted, it must be thoroughly loosened. This can be done with a vertical drainage machine. Vertical drainage is most effective when done subsequent to a top dressing of the area. The soil is then loosened with the vertical drainage machine, and with one or more subsequent levelings, most of the top dressing is distributed into the holes made by the drainage machine. The best time for vertical drainage is spring or fall. 

Heavy machinery for loosening compacted soil

Loosening of soil in depth

Irrigation
Water is vital for the grass. To provide the grass with optimal growth conditions, the plants should be irrigated with 1 inch (25 mm) per week according to the local evapotranspiration – and must always be based on rainfall – evapo­transpiration measures. Irrigation is required in the dry periods. Measurements of precipitation and evaporation, as well as known limit values for water deficiency enables the growth of the grass since the water consumption is tailored to suit the actual needs of the grass. If irrigation is commenced in a dry period, it is important to continue watering throughout the period. “Spot irrigation” should never be done because it will make the root network of the grass superficial and less drought-resistant.

Irrigation is easily accomplished with the right equipment

Use
Grasses are living plants, which like all other living organisms, depend on the climate. In periods without growth or with limited growth, the grass has no wear tolerance. Grass is therefore particularly susceptible in the winter, and in dry periods. An intensive use of the lawn during dry periods where the grass is not growing will result in the formation of bare spots, allowing for weed establishment.